Abstract
In the present paper, drag reduction and heat transfer enhancement were studied in a fully developed two-dimensional water channel flow. Surfactant solutions at different concentrations were used to examine the influence of surfactant additives on the skin friction drag and heat transfer coefficient. The present results show that there is no heat transfer reduction when 30 ppm of surfactant is added into the flow. With the increase of surfactant concentration to 90ppm, heat transfer was reduced by about 60%. A row of low-profile vortex generators were installed in the spanwise direction to enhance heat transfer rate over the heating surface. The effect of the vortex generators on heat transfer was examined for surfactant concentration of 90 ppm at Reynolds numbers of 7000 and 12000. The results show that the local Nusselt number is enhanced by about 200% as compared with that obtained in the surfactant solution without the use of vortex generators.
